ANKARA (Reuters) - A bill to change the Turkish constitution and usher in the executive presidency long sought by President Tayyip Erdogan has been formally presented to Erdogan, broadcaster NTV, a procedural step that will pave the way for an April referendum.

Once Erdogan approves the bill, which is he is widely expected to do, the referendum will then likely be held on a Sunday in early April.

(Reporting by Nevzat Devranoglu; Writing by David Dolan; Editing by Andrew Heavens)